Draining the crankcase of a small engine is frequently done by a home owner and not by a trained mechanic, and that process is often a messy job. Conventionally, this job is done by unscrewing a draincock or plug at the lowest point of the crankcase or fluid reservoir. The unscrewing of the drain plug is frequently associated with a spill of the oil or other liquid. Oftentimes, the drain will begin to leak before the plug is fully opened, and turning it one way or the other will cause the draining to cease or create a steadier uncontrolled flow. Obviously, uncontrolled spills are not only messy, but are adverse to the environment and sometimes dangerous, as the fluid tends to soak into whatever surface it drains to, is often difficult to clear or clean and is some times combustible.
In the past, many inventors have sought to deal with these problem by designing special drain valves. Examples of such devices include those structures found in:                Chen U.S. Pat. No. 6,609,699, OIL DRAIN VALVE;        Wickett U.S. Pat. No. 6,113,072, ACCESS PORT OR DRAIN PLUG WITH VALVE FOR LIQUID CONTAINERS;        Conklin et al U.S. Pat. No. 5,908,086, QUICK DRAIN CRANKCASE DRAIN PLUG;        Shropshire et al U.S. Pat. No. 5,411,115, OIL DRAIN PLUG;        Lombardo U.S. Pat. No. 5,407,117, OIL VALVE DEVICES FOR REMOVING USED OIL FROM DRAIN PANS OF VEHICLES;        Burdick et al U.S. Pat. No. 5,096,158, OIL DRAIN VALVE ASSEMBLY;        Martz U.S. Pat. No. 4,807,847. VALVED OIL PAN PLUG;These designs usually involved critical trigger arrangements for opening and closing the flow of fluid or devices such as balls or cams which could interfere with the smooth flow of fluid (particularly where the fluid contains solids or is pasty) or twisting of the drain plug upon weak parts of the assembly or diverting the flow from a straight gravity flow which interfered with the draining of semi-viscous fluids, like some spent heavy oils. All of these systems are believed to require relatively difficult designs or not suitable or versatile enough for most types of simple drain application or involve risk of leaks or handling of messy parts or dangerous materials to accomplish the fluid draining job.        
In the present invention, the drain valve assembly has a stem which may be threaded or otherwise inserted into the housing of an oil pan, preferably at the lowest point thereof, for smooth gravity flow from the fluid reservoir. This stem receives one end of a novel sealing barrel seated therein and extending downwardly therefrom, and arranged over the other end of the barrel is an outside housing. In the stem and housing there is an o-ring which seals the barrel into the stem and outside housing. At the free end of the outside housing, there may be a safety end cap tethered to the housing and free to be moved on to and off the free end of the barrel. Extending from the barrel in the direction of flow are integral tabs which may be pinched together to free the barrel for vertical movement so that the barrel may be pulled downwardly to open a channel through the barrel and allow the fluid to flow from the fluid reservoir, or when opened, to be lifted for closing the channel. With this arrangement, the valve or barrel is opened or closed merely by moving it upwardly or downwardly, without any twisting or switching of a valve relatively to the direction of flow, and further, only the outside of the barrel is manipulated, so that the user does not come into contact with any surface touching the fluid. The barrel may be rotated horizontally so the it is accessible from any degree on its circumference.